[PATCH v1 1/3] drm: Add helper to compare edids.

[Stanislav Lisovskiy]

Many drivers would benefit from using
drm helper to compare edid, rather
than bothering with own implementation.

Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
---
 drivers/gpu/drm/drm_edid.c | 26 ++++++++++++++++++++++++++
 include/drm/drm_edid.h     |  2 ++
 2 files changed, 28 insertions(+)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 9d8f2b952004..5f0f5197924d 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -1361,6 +1361,32 @@ static bool drm_edid_is_zero(const u8 *in_edid, int length)
 	return true;
 }
 
+
+bool drm_edid_are_equal(struct edid *edid1, struct edid *edid2)
+{
+	int edid1_len, edid2_len;
+	bool edid1_present = edid1 != NULL;
+	bool edid2_present = edid2 != NULL;
+
+	if (edid1_present != edid2_present)
+		return false;
+
+	if (edid1) {
+
+		edid1_len = EDID_LENGTH * (1 + edid1->extensions);
+		edid2_len = EDID_LENGTH * (1 + edid2->extensions);
+
+		if (edid1_len != edid2_len)
+			return false;
+
+		if (memcmp(edid1, edid2, edid1_len))
+			return false;
+	}
+
+	return true;
+}
+
+
 /**
  * drm_edid_block_valid - Sanity check the EDID block (base or extension)
  * @raw_edid: pointer to raw EDID block
diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index b9719418c3d2..8d28a6001287 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -354,6 +354,8 @@ drm_load_edid_firmware(struct drm_connector *connector)
 }
 #endif
 
+bool drm_edid_are_equal(struct edid *edid1, struct edid *edid2);
+
 int
 drm_hdmi_avi_infoframe_from_display_mode(struct hdmi_avi_infoframe *frame,
 					 struct drm_connector *connector,
-- 
2.17.1